The Ice Particle and Aggregate Simulator IPAS). Part III: Verification and analysis of ice–aggregate and aggregate–aggregate collection for microphysical parameterization

Aggregates have a variety of formations based on initial ice particle size, shape, and falling orientation, all of which influence water phase partitioning. Aggregate dimensional properties and density changes are calculated for monomer-monomer (MON-MON), monomer-aggregate (MON-AGG), and aggregate-aggregate (AGG-AGG) collection to be used by ice-microphysical models for improvement in aggregation parameterizations.

Aggregates are chosen from a database of 9 744 000 preformed combinations to be further collected (see Part II). AGG-AGG collection results in more extreme and a smaller range of aggregate aspect ratios than MON-AGG collection. A majority of aggregates are closer to prolate than oblate spheroids, regardless of collection type, except for quasi-horizontally oriented particles that have extreme aspect ratios to begin with.